The Sanitation Ladder, What Constitutes an Improved Form of Sanitation?

This study aimed to assess whether the MDG classifications and JMP sanitation ladder corresponded to hygienic proxies. Latrines were purposefully sampled in urban and rural Tanzania. Three hygienic proxies were measured: E. coli on points of hand contact, helminth at point of foot contact, and number of flies. Additionally, samples were collected from comparable surfaces in the household, and a questionnaire on management and use, combined with a visual inspection of the latrine's design was conducted. In total, 341 latrines were sampled. The MDG classifications "improved" vs "unimproved" did not describe the observed differences in E. coli concentrations. Disaggregating the data into the JMP sanitation ladder, on average "shared" facilities were the least contaminated: 9.2 vs 17.7 ("improved") and 137 E. coli/100 mL ("unimproved") (p = 0.04, p < 0.001). Logistic regression analysis suggests that both the presence of a slab and sharing a facility is protective against faecal-oral exposure (OR 0.18 95% CI 0.10, 0.34 and OR 0.52, 95% CI 0.29, 0.92). The findings do not support the current assumption that shared facilities of an adequate technology should be classified for MDG purposes as "unimproved".